7 invocations of hook_field_schema()

drupal_get_complete_schema in drupal-7.x/includes/bootstrap.inc
Gets the whole database schema.
drupal_get_schema_unprocessed in drupal-7.x/includes/common.inc
Returns the unprocessed and unaltered version of a module's schema.
field_create_field in drupal-7.x/modules/field/field.crud.inc
Creates a field.
field_read_fields in drupal-7.x/modules/field/field.crud.inc
Reads in fields that match an array of conditions.
field_update_7001 in drupal-7.x/modules/field/field.install
Fix fields definitions created during the d6 to d7 upgrade path.
field_update_field in drupal-7.x/modules/field/field.crud.inc
Updates a field.
_update_7000_field_create_field in drupal-7.x/modules/field/field.install
Utility function: create a field by writing directly to the database.